triiodothyronine--reverse and Nutrition-Disorders

Undernutrition was induced in rats submitted to food restriction from the fetal stage, and malnutrition was continued after birth until 70 days of life. Body weight was decreased to less than 50%. Plasma T4 and T3 and pituitary TSH content were determined between 8-70 days of life. In control rats, plasma T4 and T3 reached a maximum at 14 and 35 days of life, respectively, and TSH pituitary content at 45 days of life. In undernourished rats, after 8 days of life, plasma T4 and T3 and pituitary TSH content were decreased to about 50% or less, and the pattern of sequential changes observed in control rats was absent or modified. T4 and T3 concentrations were measured in heart, liver, and brain in the fetus (22 days old) and 8, 14, and 23 days after birth, as well as liver and brain 5'-deiodinases (5'D). Hepatic 5'D type I was always decreased in undernourished rats from 8-70 days after birth. Liver and heart T4 and T3 concentrations were decreased in 14-day-old undernourished rats as well as brain T3. Brain 5'D type II was decreased at 8 and 14 days, and total brain 5'D activities at 8 days. These changes occurred during the critical period for brain development (7th to 20th day) during which most processes of myelination take place and T3 brain normal levels are required.

Topics: Aging; Animals; Body Weight; Brain; Embryonic and Fetal Development; Female; Heart; Iodide Peroxidase; Liver; Myocardium; Nutrition Disorders; Organ Size; Organ Specificity; Pituitary Gland; Pregnancy; Propylthiouracil; Rats; Rats, Inbred Strains; Reference Values; Thyrotropin; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse

Topics: Aged; Humans; Nutrition Disorders; Triiodothyronine; Triiodothyronine, Reverse

We studied plasma concentrations of TSH (basal and after TRH), thyroxine (T4), 3,5,3'-triiodothyronine (T3), 3,3',5'-triiodothyronine (reverse T3; rT3), free T4 and free T3 in thirty obese subjects, twenty patients with anorexia nervosa, fifteen malnourished subjects and twenty normal weight subjects. Total serum T4 values were similar for the four groups of subjects while serum free T4 values were slightly increased in anorexia nervosa and normal in the other groups. Serum total and free T3 levels were both significantly decreased in anorexia nervosa and malnutrition, and within normal limits in obesity. The mean serum rT3 level was increased in anorexia nervosa and malnutrition while was reduced in obesity. A delay in peak response of TSH to TRH stimulation (30' rather than 20') was noted in anorexia and malnourished patients. The results suggest that these alterations of serum iodothyronines are due to a different peripheral conversion of T4 to T3 according to nutritional status.

Topics: Adolescent; Adult; Anorexia Nervosa; Female; Humans; Male; Middle Aged; Nutrition Disorders; Obesity; Thyroid Hormones; Thyrotropin; Thyrotropin-Releasing Hormone; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse

Topics: Adolescent; Adult; Humans; Infant, Newborn; Iodine; Kidney; Liver; Liver Cirrhosis; Nutrition Disorders; Thyroid Diseases; Thyroid Hormones; Thyroxine; Triiodothyronine; Triiodothyronine, Reverse